Setscrew with rotatable plastic end



March 24, 1970 M WM fill/4w a w M March 24, 1970 w my United States Patent O 3,501,993 SETSCREW WITH ROTATABLE PLASTIC END Henry F. Swenson, 22 Homehill Lane, Roseland, NJ. 07068 Filed Dec. 17, 1968, Ser. No. 784,317 Int. Cl. F16b 35/00 US. Cl. 85-1 5 Claims ABSTRACT OF THE DISCLOSURE A setscrew is provided with a protruding resilient end member such as nylon, which end member is independently rotatable in or on the shank or body portion of the setscrew. This resilient portion is rotatably mounted and permits the body of the setscrew to be advanced in a hub until the resilient end portion is brought against a threaded or curved portion which is to be secured and to be tightened thereagainst without having the face of the protruding resilient end destroyed or deformed by abrading during the rotation of the setscrew.

BACKGROUND OF THE INVENTION Field of the invention The field of art to which this invention pertains is found generally in the class of Rod Joints or Couplings and in particular in the subclass of collar, pulley or lever and shaft and even more particularly in the subclass entitled setscrew, pin or bolt.

Description of the prior art In the use of setscrews for retaining members on shafts, which shafts may be plain, with keys or with threads, it has been found highly desirable in most instances to use a soft face on the retaining member so that a burr is not raised upon the engaged member. In anticipation thereof, there are setscrews available wherein a nylon inserted tip is mounted in the end of the body of the setscrew. However, as far as is known, these nylon inserted tips have been a force fit in the end of the set screw body. When such a setscrew is turned tightly against a curved surface or against a threaded surface, the nylon end or soft insert, as it is rotated with the threaded body, is abraded and becomes mutilated or destroyed until it is rendered unsuitable for re-use. In certain of the presently commercially available setscrews, the setscrews are made from tubing and have a swaged drive socket formed in one end. The other end of the tubing receives and retains the soft tip which is a plug of nylon or other resilient material. This tip or plug, as the setscrew is turned forwardly, expands outwardly and rearwardly toward the retaining body, and is often cut when the setscrew is advanced against a curved surface or some other surface in which there is an irregularity. The abrading action providing the tendency of the fixed plug insert to be mutilated or destroyed is avoided in the instant invention.

BRIEF SUMMARY OF THE INVENTION A solid setscrew body has its end shaped so as to receive and retain a nylon plug or a like resilient, partially resilient or otherwise soft member, which member is rotatable on or in the end of the screw body as the screw is advanced forwardly into retaining or looking engagement. In particular, the setscrew rotatably retains a nylon member which is mounted in one of several socket designs as shown in the drawings. Each socket provides a shoulder or face against which the thrust of the softer member may be received as the screw is advanced.

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INTENT OF THE DISCLOSURE Although the following disclosure offered for public dissemination is detailed to insure adequacy and aid in understanding of the invention, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how it may later be disguised by variations in form or additions of further improvements. The claims at the end hereof are intended as the chief aid toward this purpose, as it is these that meet the requirements of pointing out the parts or improvements in which the inventive concepts are found.

There has been chosen several embodiments of a solid setscrew body with a rotatable protruding resilient end as adapted for use in retaining hubs and the like to shafts both threaded and unthreaded. These embodiments have been chosen for the purposes of illustration and description as shown in the accompanying drawings wherein:

BRIEF DESCRIPTION ON THE DRAWINGS FIG. 1 represents a setscrew partly in section and showing a plastic insert seated within a shallow recess in the end of the setscrew and with the metal shoulder portion which retains the plug turned inwardly to slidably engage the plastic plug;

FIG. 2 represents a sectional and fragmentary view of the end of a setscrew similar to that of FIG. 1, however, the metal retaining shoulder portions of this embodiment extend outwardly from the threaded end of the setscrew with the outer end portions turned inwardly to slidably engage the plastic plug;

FIG. 3 represents a sectional and fragmentary view of an end of a setscrew wherein a nylon cap is pressed over the protruding end of the setscrew, the cap having inturned engaging lips acting as a retaining collar for the p;

FIG. 4 represents a sectional and fragmentary view of an end of a setscrew wherein the nylon tip or plug has an additional plastic or metal ring mounted on the inner end of the plug to provide a shoulder member disposed to fit within a formed recess in the socket of the body of the setscrew;

FIG. 5 represents a sectional and fragmentary view of an end of a setscrew having a socket with ridges formed in the sidewall, the inserted plug also is provided with corresponding ridges formed in its sidewall;

FIG. 6 represents a sectional and fragmentary view of an end of a setscrew wherein the resilient plug is retained by means of a small cross pin carried in the body of the screw;

FIG. 7 represents a sectional and fragmentary view of an end of a setscrew wherein the end and socket are formed with a contour adjacent an undercut recess;

FIG. 8 represents a sectional and fragmentary view of an end of a setscrew which is a modification of the setscrew of FIG. 7 wherein a small chamfered seat is adjacent an undercut recess and forms the major portion of the plug retaining means;

FIG. 9 represents a sectional and fragmentary view of an end of a setscrew wherein the retaining portion of the rotating plug is forced into an undercut recess in the end of the screw body;

FIG. 10 represents a sectional and fragmentary view of an end of a setscrew wherein the plastic member is a cap member fitted over an outwardly expanded protruding end portion of the setscrew;

FIG. 11 represents a sectional view of a plastic plug or rotating member prior to its insertion into the socket of a setscrew, and

FIG. 12. represents a sectional and fragmentary view of an end of a setscrew wherein the plug member of FIG. 11 is mounted in the socket of a solid setscrew body.

In the following description and in the claims, various details will be identified by specific names for convenience; these names, however, are intended to be generic in their application. Corresponding reference characters refer to like members throughout the several figures of the drawings.

The drawings accompanying, and forming part of, this specification disclose certain details of construction for the purpose of explanation of the broader aspects of the invention, but it should be understood that structural details may be modified in various respects without departure from the concept and principles of the invention.

DESCRIPTION OF THE SETSCREW OF FIG. 1

Referring now to FIG. 1, it is to be noted that a hollow head setscrew body has a shallow recess 22 formed in its end. In this recess a nylon insert or plug 24 is disposed to be mounted. The inner face 25 of this nylon insert or plug 24 is flat and rests upon a like surface formed in the recess 22 of the setscrew. Adjacent the inner flat' surface 25, the sidewall of the plug is provided with a shallow groove 26 into which a small inwardly formed ring portion 28 of the setscrew extends. This ring portion 28 acts as a retaining collar so as to prevent the insert 24 from falling out of the recess 22 while permitting the setscrew body 20 to turn in a threaded hole.

In the assembly of the setscrew of FIG. 1, it is contemplated that the shoulder portion 28 may be made as an upstanding or outwardly extending portion of the end face 29 of the setscrew body 20. After the insert 24 has been mounted in the recess 22, this shoulder portion 28, by means of a seating or swaging tool or by means of a spinning operation, is displaced into the position shown in FIG. 1.

DESCRIPTION OF THE SETSCREW OF FIG. 2

Referring next to FIG. 2, there is shown a setscrew body 30 having a recess 32 formed therein. This recess has an upstanding shoulder portion 34, which shoulder portion, as the setscrew body is formed, is made as an outstanding ring with a substantially straight bore and fiat bottom. An insert 36, preferably of nylon and having a shallow groove portion 37 formed in its sidewall, is mounted in this socket with the inner flat face 38 resting on the flat bottom of the socket. To retain the insert 36 in the socket 32, the upstanding ring portion, as in the setscrew assembly of FIG. 1, is forced inwardly by means of a seating tool or by spinning so that the ring portion 39 acts as a collar which enters and slidably engages the recess 37 of the insert 36 to rotatably retain this insert in the socket.

DESCRIPTION OF THE SETSCREW OF FIG. 3

Referring next to FIG. 3, there is shown a setscrew body 40 which has its end formed with an extending shouldered end 42 which has an enlarged outer diameter 43. A nylon or like plastic cap 44 is sized to slide over the enlarged portion 43 so that a flat inner base 45 will seat on a like fiat end of shouldered portion 42. After the fiat base is brought into engagement with the end of shouldered portion 42, a shoulder portion 46 is caused to be formed in cap 44 by being swaged inwardly by means of a clamping tool or by spinning to cause the shoulder 46 to slidably engage a groove in shouldered end 48. The shouldered portion 46 formed on the plastic cap 44 rotatably retains this cap on the extending shouldered end 42.

DESCRIPTION OF THE SETSCREW OF FIG. 4

Referring next to FIG. 4, there is shown a setscrew body 50 formed with a recess 52 having an enlarged portion 53 formed at the inward end of said recess. A plastic insert or plug 54 which is preferably of nylon has a ring member 56 mounted on the inner end thereof.

This ring is shown as being formed with a tapered socket and is preferably retained on a like-formed end of the insert 54 in a pressed fit condition. The ring member 56 is at least slightly resilient and may be of soft metal or of plastic. The recess 52 at its main o'utbore portion is a few thousandths of an inch smaller in diameter than at the enlarged inner portion 53 so that this enlarged recess portion acts as a retainer for the ring 56 to prevent the plastic insert 54 from being withdrawn from the recess 52 after the insert has been rotatably assembled in the recess 52 of the body 50.

It is contemplated that in the assembly of the resilient member 54 in the enlarged portion 53 of the recess the ring 56 is slightly compressed as it is pushed through the reduced diameter portion of the socket 52. After ring member 56 enters the enlarged portion 53, it expands to provide a sliding and retaining fit in the enlarged recessed portion 53.

DESCRIPTION OF THE SETSCREW OF FIG. 5

Referring next to FIG. 5, there is shown a setscrew body 60 having a bore 62 wherein small ridge portions 64 are formed in the wall and extend inwardly of a common diameter of the bore. A plastic insert or plug 66 having a shouldered diameter portion 68 slightly smaller than the ridge portions 64 has this portion 68 pushed into the socket 62. The outer wall of the diameter portion 62 engages these inwardly disposed annular ridges or rings 64 and cut small mating grooves in the plastic surface as the setscrew body 60 is turned. These grooves, as they are cut in the plastic insert, slidably engage these rings to provide means for rotatably retaining the insert 66 in the socket.

DESCRIPTION OF THE SETSCREW OF FIG. 6

Referring next to FIG. 6, there is shown a setscrew body 70 having an end recess 72 formed therein. A plastic insert 74 is mounted in recess 72 and has an arcuate groove 75 formed in the sidewall and at a determined distance from the inner end 76 of the insert. A locking pin or dowel 78 is mounted and retained in a transversely drilled hole in the body of the setscrew. This pin 78, as it is inserted in the drilled hole of the body, tangentially enters groove 75 so as to rotatably retain the plastic body 74 in recess 72.

DESCRIPTION OF THE SETSCREW OF FIG. 7

Referring next to FIG. 7, there is depicted a setscrew body 80 having a recess 81 formed in the center of the end of the body. This recess has a reduced shoulder portion 82 formed at the outer end of said recess. Adjacent to and outwardly of this recess 81 there is formed a V-shaped groove 83 in the face or end of the setscrew body 80. A plastic plug member 84 is preferably made of nylon and has a contoured face including a complementary V-shaped protrusion sized to mate with the V-groove 83. This plug is mounted onto the end of the setscrew body 80 with the V-groove portions of the plug member and screw body end mating with each other at the groove portion 83. An inwardly extending stern portion 85 of the plug is locally undercut and is sized so as to be rotatably retained by shoulder portion 82. The end of the stem has an enlarged diameter portion 87 sized so that this plastic shoulder is rotatably retained in the recess 81 of the setscrew body 80.

DESCRIPTION OF THE SETSCREW IN FIG. 8

Referring next to FIG. 8, there is depicted a setscrew body 90 formed with chamfered shoulder 92 terminating at an undercut recess 94. A stem portion 95 of a plug member 96 is sized and adapted to seat in and be retained in recess 94. The inwardly sloped face surface 97 of the plug member is contoured to mate with and to seat upon chamfer 92 and is rotatably retained by the stem portion 95 in the recess 94. The retention of the plug is by means of an inwardly extending ring portion 98 mating in a groove formed in the plug stem 95.

DESCRIPTION OF THE SETSCREW OF FIG. 9

Referring next to FIG. 9, there is shown a setscrew body 100 having an inwardly expanding tapered socket recess 102 formed therein. The recess has its larger diameter formed at the inner end of the recess and within this recess 102 a plastic plug member 104 is rotatably mounted by means of a tapered end 105. The tapered end 105 expands outwardly to seating surface 106 with the larger diameter portion rotatably retaining the plug in the recess. This tapered end portion 105, during assembly, is compressed a few thousandths of an inch and after insertion the tapered end expands to retain the plug in the recess. The insertion of the tapered end may be by means of a special tool or by using a heat differential of the body and plastic part so that when the parts are brought to a like normal temperature they conform to the sliding fit as shown in FIG. 9.

DESCRIPTION OF THE SETSCREW OF FIG.

Referring next to FIG 10, there is shown a setscrew body 110 having a tapered stem 112 formed to extend outwardly from a flat face 113. The taper of the stem is sloped so that the outer face end is the larger diameter. A nylon cap 115 has a tapered recess 116 formed in its inner face. The cap 115, after being placed in position on stem 112, is then swaged or by spinning the sidewall the recess is moved inwardly to be slidably disposed against the tapered stern. This reshaping of the recess permits the cap 115 to be rotated on the stem 112 while still being retained on the stem. The recess, after it is reshaped, is tapered inwardly toward the flat face 113 and tapered stem 112 of the screw body.

DESCRIPTION OF THE SETSCREW OF FIGS. 11 AND 12 Referring finally to the setscrew of FIGS 11 and 12, there is shown in FIG. 11 and in section, a plastic plug 120 having a disc portion 122 attached by a stem portion 123 to the main body of the plastic plug. A setscrew body 125 has a recess 127 formed axially therein. The recess 127, as shown, has straight sides and is slightly smaller in diameter than is the diameter of the disc portion 122 of the plug. To assemble, the disc 122 is forced into the recess 127 until the disc bottoms on or against the inner face of the recess. The diameter of the main body of the plug is contemplated as being a rotating fit in the recess. After assembly, the disc 122 snugly engages the sidewall of recess 127 and in the manner of a bowed lock spring or wedge resists forces tending to pull or otherwise remove the plug from said recess.

USE AND OPERATION In the use and operation of the rotatably mounted plastic tipped setscrews shown in the several embodiments of FIGS. 1 through 12, it is to be noted that the several setscrew bodies are each contemplated as being a solid member with the end formed to receive and retain a rotatable nylon plug. This plug has its end shaped so as to accept a thrust load and transfer this load to the screw body while still rotatably retaining the plug as it is mounted in the body.

In use, the assembled setscrew is usually a socket headed screw and is used to retain or lock a member, such as a hub, on a shaft. The shaft may include a key and keyway or may have a threaded portion with the part to be retained acting as a nut. As the plastic plug is relatively soft compared to the metal member which is engaged, it is highly desirable that the plug not be abraded, cut or deformed as it is tightened against the shaft. With the plug rotatably mounted in the screw body, as the screw is tightened, the soft plastic conforms to the engaged surface without cutting, tearing or grinding. The

withdrawal of such a setscrew from a hub or the like raises no problems as the plug does not turn until free of any inhibiting contour or engagement.

Terms such as up, down, bottom, top, front, back, in, out, and the like are applicable to the embodiments shown and described in conjunction with the drawings. These terms are used merely for the purposes of description and do not necessarily apply to the position in which the setscrews and their rotatable plastic ends may be constructed or used.

The conception of the rotatable and retained plastic plug in combination with a solid screw body and its many applications is not limited to the specific embodiments shown and protection is sought to the broadest extent the prior art allows.

What is claimed is:

1. A setscrew having a solid externally threaded body member disposed to receive and rotatably retain a protruding resilient end member mounted in a shallow recess formed in one end of the body, the setscrew in combination including: a circular recess of shallow depth and having a relatively fiat base, the recess formed in an end of the body member receiving and engaging a like diameter portion of a resilient protruding end member formed of synthetic plastic material so as to rotatably retain said end member on the end of the body, said resilient protruding member being generally cylindrically shaped and of a diameter less than the root diameter of the threads on the body member with a flat inner end and with a shallow, narrow groove having a generally cylindrical inner surface formed in its side wall, the groove disposed at a determined distance from the inner end of the protruding end member and a narrow ringlike portion formed on the end of the setscrew and adjacent the recess, said ringlike portion being displaced inwardly of the recess end and into rotatable engagement with the shallow groove in the side of the protruding end member, said ringlike portion on the end of the body after being displaced into rotatable engagement with the shallow groove being contoured as a substantially flat end on the screw body, the outer end of the protruding end member extending beyond the end of the body.

2. A setscrew having a solid externally threaded body member disposed to receive and rotatably retain a pro truding plastic end member mounted in a recess formed in one end of the body, the setscrew in combination including: (a) a circular recess of a determined depth formed in one end of the body member, said recess having an enlarged diameter portion at its inner end, and a synthetic plastic protruding end member having a stem portion of a diameter being rotatably retained in the circular recess in the body; (b) a deformable cylindrical portion carried on one end of the stem portion and of a greater diameter than the adjacent stem portion, said cylindrical portion rotatably engaging the enlarged diameter portion of the recess, said cylindrical portion being of a diameter slightly greater than the stem-retaining circular recess portion extending from the one end of the screw body to the enlarged diameter portion of the recess; (c) an annular V-groove formed in the face of the one end of the body member, said V-groove positioned radially outwardly of an concentric with the circular recess and, (d) an annular V-shaded protruding portion formed on the protruding end member and rotatably engaging and retained by the V-groove in the end of the body, the protruding end member projecting beyond the end of the screw body and being of a diameter less than the root diameter of the threads on the body.

3. A setscrew having a solid externally threaded body member disposed to receive and rotatably retain a protruding synthetic plastic end member mounted on one end of the body, the setscrew in combination including: (a) a circular recess formed in one end of the body, the recess having a plurality of inwardly extending concentric, annular ridge portions of shallow extent formed in its sidewalls, and (b) a stem portion formed on the protruding plastic member, the stem portion being press fit into the recess, the stem portion of the protruding plastic end member being of a hardness which is deformable upon sliding engagement with the ridges, whereby mating grooves are formed in the side wall, the grooves so formed receiving and engaging the concentric ridge portions of the recess to retain the protruding end member in the setscrew body, the protruding end member projecting beyond the one end of the body and being of a diameter less than the root diameter of the threads on the body.

4. A setscrew having a solid externally threaded body member disposed to receive and rotatably retain a protruding resilient end member formed of synthetic plastic material mounted on one end of the body, the setscrew in combination including: (a) a circular recess of determined diameter and depth formed in one end of the body; (b) a stem formed on one end of the protruding end member, the stem having a resilient disc end portion of a diameter slightly larger than the diameter of the circular recess when the disc is in its undeformed condition, and an intermediate stem portion sized to be a sliding fit in the recess, the intermediate portion disposed adjacent the disc and connecting the disc to a main body portion of the protruding end member, the disc being inserted into the recess whereby it is bowed to form a RAMON s. BRITTS.

conical locking portion which is biased outwardly to engage the side wall of the recess as a narrow ring so as to be rotatable in said recess but which as it is biased outwardly jams against the wall of the recess to prevent withdrawal of the disc from the recess, the other end of the protruding end member extending beyond the one end of the body and being of a diameter less than the root diameter of the threads on the body.

5. A setscrew as in claim 4 wherein the disc, stem and main body of the protruding end member is formed from one piece.

References Cited UNITED STATES PATENTS 880,948 3/1908 Wilhelm et a1. 1,107,177 8/1914 Noble. 2,086,221 7/ 1937 Gwyn. 2,560,080 7/ 1951 Bottome.

FOREIGN PATENTS 113,394 2/1918 Great Britain.

585,830 2/1947 Great Britain.

743,140 1/ 1956 Great Britain. 1,062,372 3/1967 Great Britain.

Primary Examiner 

